1. Field of the Invention
The present invention relates to urethane-modified isocyanurate foams characterized by improved insulating and flame-retardant properties. More particularly, the invention relates to the incorporation of chloro-alkanol moieties into a urethane-modified isocyanurate foam.
2. Prior Art
The preparation of urethane-modified isocyanurate foams is well known in the art. Generally these foams are prepared by catalytically condensing an organic polyisocyanate with a polyol in the presence of a trimerization catalyst and optionally a catalyst which promotes the urethane reaction. Although, the resulting foams exhibit good physical and flame-retardant properties, they generally display poor insulating properties which is expressed by the K- and aged K-factor. The K-factor is a measurement of the insulating properties (thermoconductivity) and aged K-factor indicates the loss in insulating properties with time. It is to overcome the poor insulating properties of urethane-modified isocyanurate foams to which the present invention is directed.
The most pertinent of the prior art references relating to the preparation of urethane-isocyanurate foams known to applicants is U.S. Pat. No. 3,891,579. This patent teaches the preparation of these foams employing halogenated aliphatic alkanols as accelerators for the trimerization reaction. It is taught in this patent that the use of the halogenated alkanols provides foams having improved flame-retardant properties as well as reduced friability. The invention described herein differs from that of the aforementioned patent in the amounts of chloroalkanol employed, and in the use of the chloro-alkanols as reactants in the preparation of foams having improved insulating and flame retardant properties.